I have both the EQ and the PAC LC-1. The Pac does a good job if you only want to reduce the sound level as I do with my bow speakers. The EQ adds lots more for just a few bucks more, as clubmyke is alluding to with his questions. If you only want to kill the tower speakers the simplest solution is a switch in the turn on lead to the tower amp.

Same thing here Rod... Speakers inside the boat are on the front channel through the AMP and the tower speakers are on the rear channel through their own amp. Works great! Anyone can use it because it's sooo easy.